The  Annual  Howison  Lecture 
1926 


THE  PRAGMATIC  ELEMENT  IN 
KNOWLEDGE 

CLARENCE  IRVING  LEWIS 


University  or  California  Publications  in  Philosophy 
Volume  6,  No.  3,  pp.  205-227 


UNIVERSITY  OF  CALIFORNIA  PRESS 
BERKELEY,  CALIFORNIA 
1926 


UNIVERSITY  OF  CALIFORNIA  PUBLICATIONS 


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PHILOSOPHY 
Vol.  I 


McGilvary.   The  summum  bonum   $  .2 

Mezes.   The  essentials  of  human  faculty. . .  25 

Stratton.   Some  scientific  apologies  for  evil.  15 

Rieber.  Pragmatism  and  the  a  priori  20 

Bakewell.   Latter-day  flowing  philosophy  20 

Henderson.   Some  problems  in  evolution  and  education  10 

Burks.   Philosophy  and  science  in  the  study  of  education  15 

Love  joy.   The  dialectic  of  Bruno  and  Spinoza  35 

Stuart.   The  logic  of  self-realization  30 

de  Laguna.   Utility  and  the  accepted  type   .20 

Dunlap.   A  theory  of  the  syllogism  

Overstreet.   The  basal  principle  of  truth  evaluation  

Vol.  II 

Overstreet.   The  dialectic  of  Plotinus  


Hocking.   Two  extensions  of  the  use  of  graphs  in  formal  logic  

Hocking.    On  the  law  of  history  

Adams.   The  mystical  element  in  Hegel's  early  theological  writings. 

Parker.   The  metaphysics  of  historical  knowledge  

Boas.   An  analysis  of  certain  theories  of  truth  =  

Vol.  Ill 

Eieber.   Footnotes  to  formal  logic  Cloth,  $2.00 ;  paper,  1.50 

Prall.  A  study  in  the  theory  of  value.   1.00 


THE  ^PRAGMATIC  ELEMENT  IN  KNOWLEDGE 


BY 

CLARENCE  IRVING, LEWIS 


University  of  California  Publications  in  Philosophy 
Howison  Lecture  for  1926 
Volume  6,  No.  3,  pp.  205-227 
Issued  December  15,  1926 


University  of  California  Press 
Berkeley,  California 


Cambridge  University  Press 
London,  England 


3JD 

\(o  I 


THE  PRAGMATIC  ELEMENT  IN 
KNOWLEDGE 

BY 

CLAEENCE  IEVING  LEWIS 


There  are  three  elements  in  knowledge;  the  given  or  im- 
mediate data  of  sense,  the  concept,  and  the  act  which  interprets 
the  one  by  means  of  the  other.  In  the  matrix  of  thought  these' 
are  inseparable;  they  can  only  be  distinguished  by  analysis. 
Not  all  would  agree  that  even  just  analysis  can  separate  them. 
In  fact,  theories  of  knowledge  might  be  classified  by  their  in- 
sistence upon  one  or  another  of  these  three  and  the  attempt  to 
comprehend  the  other  two  within  it.  Emphasis  on  the  given 
or  immediate,  characterizes  the  mystic  and  Bergson's  "pure 
perception."  Subordination  of  the  other  two  to  the  conceptual 
element,  means  idealism  or  some  form  of  rationalism.  Prag- 
matism is  distinguished  by  the  fact  that  it  advances  the  act  of 
interpretation,  with  its  practical  consequences,  to  first  place. 

If  one  ask  for  a  rough  and  ready  expression  of  the  pragmatic 
creed,  I  suppose  one  will  be  likely  to  receive  the  answer,  "The 
truth  is  made  by  mind."  Qualification,  of  course,  is  needed  at 
once.  There  is  equal  insistence  that  the  making  of  truth  is 
directed  to  some  practical  situation.  And  a  practical  situation 
implies  brute  fact,  something  given,  as  one  element  of  it.  The* 
other  element  is  a  human  being  with  his  needs  and  interests. 
If  the  pragmatist  emphasizes  the  importance  of  such  needs  in 
determining  our  human  truth,  it  is  equally  just  to  remark  that, 
without  the  brute  fact  of  the  given,  the  problem  of  meeting  these 
needs  would  not  arise.  Nor  would  there  be  anything  which 
could  determine  that  one  way  of  meeting  them  should  succeed 
and  another  fail.  If  the  pragmatist  maintains,  then,  that  the 
truth  is  made,  at  least  he  does  not  believe  that  it  is  made  out  of 
whole  cloth. 


191682 


206 


University  of  California  "Publications  vn  Philosophy  [Vol.6 


Moreover,  in  conceiving  that  truth  and  knowledge  represent 
active  interpretation  by  the  mind,  pragmatism  is  not  alone. 
Idealism  likewise  stresses  the  creativity  of  thought.  Indeed, 
the  idealist  outruns  the  pragmatist  in  this  respect,  conceiving 
that  the  object,  and  so  the  situation  to  be  met  by  knowing,  has 
ultimately  no  existence  independent  of  the  mind. 

The  difference  between  the  two — or  a  difference — lies  in  this; 
that  for  the  idealist  'mind'  means,  in  the  last  analysis,  generic 
mind,  the  common  human  mind,  or  the  ideal  mind  imperfectly 
manifest  in  us,  the  Absolute.  While  for  the  pragmatist  minds 
are  individual,  ultimately  distinct,  and  capable  of  idiosyncracy. 
Such  personal  or  racial  peculiarities,  or  differences  which  time 
makes  in  the  prevailing  temper,  may  find  their  expression  in 
the  way  minds  meet  the  situations  which  confront  them.  And 
so  truth  may  be  somewhat  personal,  and  may  change  with 
history.    It  is  not  rooted  in  fixed  categories  which  are  a  priori. 

These  are,  then,  the  bare  fundamentals  of  the  pragmatist 
position  concerning  knowledge :  that  knowledge  is  an  interpre- 
tation, instigated  by  need  or  interest  and  tested  by  its  conse- 
quences in  action,  which  individual  minds  put  upon  something 
confronting  them  or  given  to  them.  On  any  theory,  it  is  to  be 
expected  that  minds  will  largely  coincide  and  that  agreement, 
for  various  obvious  reasons,  will  be  the  rule.  But  the  extent  and 
manner  of  such  coincidence  is,  for  pragmatism,  something  to  be 
noted  in  particular  cases,  not  simply  the  result  of  universal 
human  reason. 

As  I  have  suggested,  the  validity  of  this  general  type  of 
conception  can  be  tested  by  studying  the  nature  and  importance 
in  knowledge  of  the  pragmatic  element  of  interpretation,  and 
its  relation  to  the  other  two,  which  we  may  refer  to  as  'the 
concept'  and  'the  given'  respectively. 

Suppose  that  we  take  some  outstanding  example  of  knowl- 
edge, and,  using  it  as  a  paradigm,  attempt  thus  to  assess  the 
significance  of  interpretation.  Whatever  example  Ave  choose 
will  be  of  some  particular  type,  and  we  must  be  on  our  guard 
against  mistaking  as  general  features  of  knowledge  what  are 


1926] 


Lewis:  The  Pragmatic  Element  in  Knowledge 


207 


only  typical  of  special  cases.  But  if,  from  lack  of  time,  we 
thus  concentrate  on  a  single  illustration,  it  should  represent 
knowledge  at  its  best.  For  this  reason,  !  propose  the  example 
of  geometry.  Mathematics  comes  very  close  to  our  ideal  of 
knowledge  at  least  in  the  important  respect  of  relative  certainty. 
And  in  the  whole  field  of  mathematics,  geometry  offers  the  best 
example  because  of  the  concreteness  of  its  applications. 

The  last  quarter-century  of  mathematical  study  represents 
the  historical  fruition  of  a  great  many  previous  researches  and 
discoveries,  so  that  today  we  can  feel  much  surer  that  we  under- 
stand the  nature  of  mathematical  knowledge  than  it  ever  has 
been  possible  for  men  to  feel  before.  Three  important  results 
emerge  from  this  study.  The  first  is  the  discovery  that  all 
mathematics,  and  not  geometry  only,  can  be  developed  by  the 
deductive  method.  A  relatively  few  definitions  and  initial 
assumptions  suffice  to  give  us  all  the  rest  of  any  branch  of 
mathematics,  such  as  complex  algebra  or  projective  geometry. 

The  second  of  these  results  is  a  necessary  consequence  of  the 
first:  All  mathematics  is  abstract  in  the  sense  of  being  indepen- 
dent of  any  and  every  possible  application.  Because  if  all  the 
theorems  follow  logically  from  the  definitions  and  postulates, 
then  we  can  arbitrarily  alter  the  things  which  we  let  the  terms, 
such  as  'point'  and  'line,'  mean,  without  in  the  least  disturbing 
any  step  in  the  proofs.  Whatever  'point'  and  'line'  may  mean, 
given  these  assumptions  about  them,  these  consequences — the 
rest  of  the  system — must  also  hold  of  them,  because  the  theorems 
follow  from  the  assumptions  by  pure  logic.  Thus  for  any  mathe- 
matical system,  there  will  be  many  possible  applications,  though 
very  likely  only  one  or  two  of  these  will  have  any  practical 
importance.  You  can  let  'points'  mean  the  members  of  a  set 
of  clubs  governed  by  certain  rules,  or  you  can  let  them  represent 
what  are  usually  described  as  "spheres  one  inch  in  diameter." 
Similarly,  the  a's  and  5's  and  re's  of  complex  algebra  may  rep- 
resent numerical  magnitudes  or  you  may  let  them  represent  the 
array  of  points  in  space.  In  this  last  case,  both  the  applications 
mentioned  are  practically  important. 


L'llS 


University  Of  California  Publications  in  Philosophy        [VOL.  6 


The  third  step  was  tin*  logical  culmination  indicated  by  the 
two  preceding.  It  was  discovered  that  we  can  dispense,  in 
mat  hematics,  with  all  the  initial  assumptions  except  the  defini- 
tions. That  is.  all  the  truths  of  mathematics  follow  from  the 
definitions  of  the  terms  used,  without  any  further  assumptions 
whatever  except  logic  or  the  principles  of  proof.  This  third  step 
could  only  he  proved  possible  by  actually  carrying  it  out.  The 
stupendous  labor  of  thus  developing  the  fundamental  principles 
of  mathematics  merely  from  exact  definitions  of  terms,  by  pure 
logic  was  performed  by  Mr.  Russell  and  Mr.  Whitehead  in 
Principia  Mathematical 

Our  main  interesl  in  all  this  is  that  it  definitely  proves  some- 
thing that  Plato  ventured  to  assert  two  thousand  years  ago;  that 
our  knowledge  of  mathematics  is  quite  independent  of  that  sense- 
experience  which  suggests  it  to  us  and  is  the  practical  motive 
for  our  study  of  it.  A  club  of  thorough-paced  mathematicians 
could  retire  from  the  world  of  sense,  provided  that  were  some- 
how possible,  and  not  interrupt  their  discussions  in  the  least. 
They  would  need  a  means  of  communication,  of  course,  and  some 
sort  of  counters,  such  as  words  or  tally-marks,  as  the  common 
currency  of  their  discussion.  But  no  application  to  sense-things 
is  otherwise  of  the  least  importance  to  them.  Often  they  do  not 
assign  any  meaning  at  all  to  their  «'s  and  b's;  the  letters  them- 
selves are  good  enough  symbols  to  serve  all  their  interests. 

Thus  we  discover  that  the  content  of  pure  mathematics  is 
simply  the  deductive  or  logical  order  of  purely  logical  entities, 
a  sort  of  elaborate  logical  pattern  of  abstract  terms  without 
any  denotation  at  all. 

"But,"  you  say,  "who  wants  that  kind  of  mathematics? 
Who  cares  whether  it  is  possible  or  not?"  I  must  not  pause  to 
answer  that  question  in  detail  beyond  pointing  out  the  relation 
which  the  business  of  pure  mathematics  now  bears  to  that  of 
the  practical  man.  The  mathematician  is  a  sort  of  maker  of 
patterns.  He  keeps  a  stock  of  them  wdiich  is  already  bigger  than 
anybody  has  found  a  need  for.  He  has  an  infinite  number  of 
J  Vol.  1  published  in  1910. 


1926] 


Lewis:  The  Pragmatic  Element  in  Knowledge 


209 


different  geometries,  for  example,  all  just  as  good  from  his 
point  of  view  as  Euclid,  and  such  curiosities  as  quaternions  and 
systems  containing  curves  that  have  no  tangents.  Mostly  he 
develops  these  from  pure  intellectual  curiosity.  He  is  exploring 
the  Platonic  heavens,  and  it  may  seem  as  important  to  him  as 
measuring  the  earth.  Sometimes  the  practical  man  borrows 
one  of  these  patterns  ready-made  and  finds  for  it  a  previously 
unsuspected  application.  Some  of  the  most  important  advances 
in  physical  science  have  come  about  in  just  this  way. 

But  our  interest  in  this  lies  in  the  nature  which  the  truth  of 
abstract  mathematics  is  revealed  to  have.  Three  points  are 
important : 

1.  Assuming  logic  or  common  modes  of  valid  proof,  the 
truths  of  mathematics  are  quite  independent  of  any  world  of 
sense,  and  hence  independent  of  given  experience,  so  far  as 
given  experience  means  perceptible  sense-qualities.  If  there 
were  two  mathematical  minds,  one  on  the  Earth  and  one  on 
Mars,  their  experience  and  their  sense-organs  might  differ  in 
any  way  you  can  imagine,  and  still  if  only  they  shared  a  com- 
mon logic  or  modes  of  valid  thinking,  all  they  would  need  would 
be  some  method  of  communication  in  order  to  have  all  the 
truths  of  mathematics  in  common. 

2.  In  such  abstract  mathematics,  the  whole  of  all  truth  is 
open  to  any  logical  mind,  provided  we  know  precisely  what  the 
terms  are  defined  to  mean — that  is,  how  they  are  logically 
related.  To  bring  out  the  point,  let  us  contrast  mathematical 
and  empirical  or  sense-knowledge  from  the  point  of  view  of 
learning.  You  see  this  desk.  It  is  a  thing  of  sense.  Suppose 
that  we  carry  away  with  us  whatever  knowledge  we  gain  now 
as  we  look  at  it.  And  then  suppose  tomorrow  someone  ask, 
"Is  there  a  knot  on  the  under  surface  of  the  top  of  this  desk?" 
We  do  not  know.  Not  only  that,  but  we  might  be  the  master 
minds  of  all  the  ages  and  have  thought  about  it  continuously 
during  the  interval,  and  still  we  could  not  know.  Nothing  but 
a  further  experience,  of  us  or  someone  else,  could  possibly 
determine  the  question. 


210 


University  of  California  Publications  in  Philosophy  [Vol.6 


Bui  nmv  suppose  that  someone  write  down  here  the  initial 
principles  of  some  mathematical  system— say  Euclid's  geometry. 
We  may  take  thai  knowledge  away  with  us,  and  there  is  abso- 
lutely no  mathematical  truth  of  that  system  which  we  could 
not  Learn  merely  by  thinking  about  it. 

3.  An  obvious  point  but  for  us  the  most  important  of  all: 
Mathematical  truth  is  a  little  more  certain  than  almost  any 
other  knowledge  that  we  have,  precisely  for  the  reason  indicated 
above.  We  really  do  not  need  any  further  experience  to  verify 
it,  and  no  further  experience  could  possibly  trip  us  up  and 
prove  us  wrong,  unless  we  have  been  illogical  in  our  thinking. 
It  is  the  kind  of  truth  called  a  priori,  knowable  with  certainty 
in  advance  of  any  particular  sense-experience  whatever. 

Admittedly  not  all  knowledge  is  of  this  sort.  As  soon  as 
we  raise  practical  questions  about  the  application  of  geometry 
to  space  or  of  algebra  to  stresses  and  strains,  the  situation  is  quite 
different  and  more  complex.  But  pure  mathematics  is,  I  think, 
typical  of  one  element  which  enters  into  all  knowledge.  It  is 
because  we  have  here  an  almost  clean  separation  of  this  element 
that  I  have  chosen  this  example,  which  in  other  respects  may 
be  a  little  difficult  and  uninteresting. 

.Mathematics  is  an  illustration  of  the  immensely  elaborate 
body  of  truth  which  may  rise  from  pure  concepts,  from  the 
merely  logical  relations  of  terms,  and  terms  which  need  not 
have  any  reference  to  sense-qualities  or  experienceable  things 
of  any  sort.  Moreover,  the  initial  meanings  or  relations  of 
these  terms  are  quite  arbitrary.  The  mathematician  makes  them 
what  he  will.  Often  he  chooses  them  from  intellectual  curiosity 
aboul  their  consequences,  an  interest  very  much  like  that  in  the 
possible  moves  in  a  game  of  chess.  When  such  relations  of  a 
few  terms  are  set  up,  just  as  when  a  few  rules  are  imposed  as 
conditions  of  the  game  of  chess,  the  logical  consequences  to 
which  they  give  rise  are  almost  inexhaustible  and  absolutely 
determined. 

Now  in  all  our  knowledge— particularly  in  all  science — there 
is  an  clement  of  just  such  logical  order  which  rises  from  our 


1926]  Lewis:  The  Pragmatic  Element  in  Knowledge  211 

definitions.  An  initial  definition,  as  we  may  see,  is  always 
arbitrary  in  the  sense  that  it  cannot  be  false.  In  itself  it  does 
not  tell  us  whether  anything  is  true  or  not,  or  what  the  nature 
of  existing  objects  is.  It  simply  exhibits  to  us  a  concept  or 
meaning  in  the  speaker's  mind  which  he  asks  us  temporarily  to 
share  with  him  and  symbolize  by  a  certain  word  or  phrase. 
Socially,  of  course,  it  is  important  that  such  meanings  should 
be  common,  and  that  words  be  used  in  familiar  ways.  But  if 
a  scientist  finds  a  new  concept  worth  developing,  he  may  invent 
a  technical  term  or  use  an  old  word  in  a  new  meaning  which 
he  takes  care  to  make  clear.  That  the  introduction  of  concepts 
which  are  novel  and  not  generally  shared  may  be  of  the  highest 
importance,  is  something  illustrated  by  almost  every  major 
advance  in  science.  Such  an  initial  concept,  whether  new  or 
old,  is  a  definite  logical  structure.  It  sets  up  precise  relations 
of  certain  elements  of  thought.  And  that  structure — or  the 
combination  of  a  few  such  conceptual  structures — may  give  rise 
to  logical  consequences  as  elaborate  as  mathematics  or  the  game 
of  chess. 

Indeed,  before  we  set  out  upon  any  systematic  investigation, 
we  must  have  such  initial  concepts  in  our  minds.  It  does  not 
matter  how  we  get  them ;  we  can  always  change  them  for  any 
reason,  or  for  no  reason  if  it  suits  our  whim.  The  real  reasons 
why  we  do  use  certain  concepts  is,  of  course,  practical.  That  is 
another  story,  which  I  shall  come  to.  But  however  we  come 
by  such  initial  meanings,  it  is  obvious  that  we  must  have  them 
before  we  address  ourselves  to  any  problem.  Until  we  have 
principles  of  classification  which  serve  to  distinguish  what  is 
material  from  what  is  immaterial,  what  is  a  force  from  what 
is  not  a  force,  straight  from  crooked,  rigid  from  non-rigid,  the 
simultaneous  from  the  successive,  and  so  on — that  is,  until  we 
have  certain  definite  concepts  or  meanings  in  mind,  we  cannot 
even  approach  the  problem  of  acquiring  knowledge  of  any  sort 
of  things  to  which  such  concepts  might  apply.  We  have  no 
handle  to  take  hold  of  them  by. 


University  of  California  Publications  in  Philosophy  [Vol.6 


And  whatever  our  concepts  or  meanings  may  be,  there  is  a 
truth  aboul  them  jusl  as  absolute  and  just  as  definite  and  certain 
as  in  the  case  of  mathematics.  Jn  other  fields  we  so  seldom  try- 
to  think  in  the  abstract,  or  by  pure  logic,  that  we  do  not  notice 
this.  Bu1  obviously  it  is  just  as  true.  Wherever  there  is  any 
set  of  interrelated  concepts,  there,  quite  apart  from  all  questions 
of  application  or  the  things  we  use  them  of,  we  have  generated 
a  whole  complex  array  of  orderly  relations  or  patterns  of 
meaning.  And  there  must  be  a  truth  about  these — a  purely 
logical  truth,  in  abstracto,  and  a  truth  which  is  certain  apart 
from  experience — even  though  this  is  only  a  part  of  the  truth 
which  we  want  to  discover,  and  the  rest  of  it  is  of  a  quite 
different  sort  which  depends  upon  experience. 

Ordinarily  we  do  not  separate  out  this  a  priori  truth,  because 
ordinarily  we  do  not  distinguish  the  purely  logical  significance 
of  concepts  from  the  application  of  words  to  sensible  things. 
In  fact  it  is  only  the  mathematician  who  is  likely  to  do  this  at 
all.  But  I  should  like  to  indicate  that  this  separation  is  always 
possible  and  that  it  is  important  for  the  understanding  of 
knowledge.  To  this  end,  let  me  use  the  term  'concept'  for  this 
element  of  purely  logical  meaning.  We  can  then  discriminate 
the  conceptual  element  in  thought  as  the  element  which  two 
minds  must  have  in  common — not  merely  may  have  or  do  have 
but  absolutely  must  have  in  common — when  they  understand 
each  other. 

I  suppose  it  is  a  frequent  assumption  that  we  are  able  to 
apprehend  one  another's  meanings  because  our  images  and 
sensations  are  alike.  But  a  little  thought  will  show  that  this 
assumption  is  very  dubious. 

Suppose  we  talk  of  physical  things  in  physical  terms,  and 
our  discussion  involves  physical  measurement.  Presumably  we 
have  the  same  ideas  of  feet  and  pounds  and  seconds.  If  not,  the 
thing  is  hopeless.  But  in  psychological  terms,  my  notion  of  a 
foot  goes  back  to  some  immediate  image  of  visual  so-long-ness, 
or  the  movements  which  I  make  when  I  put  my  hands  so  far 
apart,  or  to  a  relation  between  these  two.    Distances  in  general 


1926] 


Lewis:  The  Pragmatic  Element  in  Knowledge 


213 


mean  quite  complex  relationships  between  such  visual  percep- 
tions, muscle  and  contact-sensations,  the  feeling  of  fatigue,  and 
so  on.  Weight  goes  back  to  the  muscle-sensation  which  we  call 
in  New  England  the  "heft"  of  the  thing.  And  our  direct 
apprehension  of  time  is  that  feeling  of  duration  which  is  so 
familiar  but  so  difficult  to  describe. 

Now  in  such  terms,  will  your  sensory  image  of  a  foot  or  a 
pound  coincide  with  mine?  I  am  nearsighted;  your  eyes  are 
good.  Or  I  might  have  a  peculiarity  of  the  eye  muscles  so  that 
focusing  on  near  objects  would  be  accompanied  by  a  noticeable 
feeling  of  effort,  while  this  is  not  the  case  with  you.  When  it 
comes  to  reaching,  there  is  the  difference  in  the  length  of  our 
arms.  If  we  lift  a  weight,  there  is  the  difference  in  strength 
between  us  to  take  into  account.  So  it  is  with  everything.  In 
acuity  of  perception  and  .  power  to  discriminate,  there  is  almost 
always  some  small  difference  between  the  senses  of  two  indi- 
viduals, and  frequently  these  discrepancies  are  marked.  It  is 
only  in  rough  and  ready  terms  that  we  can  reasonably  suppose 
that  our  direct  perceptions  are  alike. 

Even  for  the  large  and  crude  distinctions,  what  assurance 
is  there  that  our  impressions  coincide  ?  No  one  can  look  directly 
into  another 's  mind.  The  immediate  feeling  of  red  or  rough 
can  never  be  transferred  from  one  mind  to  another.  Suppose 
it  should  be  a  fact  that  I  get  the  sensation  you  signalize  by 
saying  "red"  whenever  I  look  at  what  you  call  "violet,"  and 
vice  versa.  Suppose  that  in  the  matter  of  the  immediately 
apprehended  qualia  of  sensation  my  whole  spectrum  should  be 
exactly  the  reverse  of  yours.  Suppose  even  that  what  are  for 
you  sensations  of  pitch,  mediated  by  the  ear,  were  identical  with 
my  feelings  of  color-quality,  mediated  by  the  eye.  How  should 
we  ever  find  it  out?  We  could  never  discover  such  peculiarities 
of  mine  so  long  as  they  did  not  impair  my  powers  to  discrim- 
inate and  relate  as  others  do. 

Psychological  differences  of  individuals  are  indeed  impres- 
sive. Long  before  scientific  psychology  was  thought  of,  the 
ancient  skeptic  had  based  his  argument  on  them.    This  is  what 


214  University  Of  California  Publications  in  Philosophy        [VOL.  6 

led  Gorgias  to  say  thai  nothing  can  be  known,  and  if  anything 
could  be  known,  it  could  not  be  communicated.  There  can 
be  no  verification  of  community  between  minds  so  far  as  it  is 
a  question  of  the  Heeling  side  of  experience,  though  the  assump- 
tion thai  there  is  no  coincidence  here  seems  fantastic. 

Yet  Gorgias  was  quite  wrong  about  the  communication  of 
ideas.  That  your  sensations  are  never  quite  like  mine,  need  in 
no  way  impede  our  common  knowledge  or  the  conveying  of 
ideas.  Why  ?  Because  we  shall  still  agree  that  there  are  three 
feel  to  the  yard,  that  red  is  the  first  band  in  the  spectrum,  and 
that  middle  C  means  a  vibration  of  256  per  second.  At  the  end 
of  an  hour  which  feels  very  long  to  you  and  short  to  me,  we  can 
meet  by  agreement,  because  our  common  understanding  of  that 
hour  is  not  a  feeling  of  tedium  or  vivacity,  but  means  sixty 
minutes,  one  round  of  the  clock,  a  pattern  of  relation  which  we 
have  established  between  chronometers  and  distances  and  rates 
of  movement,  and  so  forth. 

When  we  want  to  be  sure  that  we  share  each  other's  mean- 
ings, we  define  our  terms.  Now  defining  terms  makes  no  direct 
reference  to  sense-qualities.  We  set  up  logical  relations  of  one 
term  to  others.  The  pictures  in  the  dictionary  may  help,  but 
they  are  not  necessary.  We  might  suppose  that  such  definition 
chases  one  meaning  back  into  other  meanings,  and  these  into 
still  others,  until  finally  it  is  brought  to  bay  in  some  first  (or 
last)  identity  of  meaning  which  must  be  identity  of  sensation 
or  imagery.  But  all  the  words  used  in  defining  any  term  in 
the  dictionary  are  also  themselves  defined.  There  is  no  set  of 
undefined  first  terms  printed  at  the  beginning.  The  patterns 
of  logical  relationships  set  up  by  these  interconnected  definitions 
of  terms,  themselves  constitute  the  conceptual  meanings  of  the 
terms  defined. 

To  sum  up  this  matter :  The  sharing  of  ideas  does  not  neces- 
sarily  depend  on  any  identity  of  sense-feeling.  It  requires  only 
a  certain  fundamental  agreement  in  the  way  our  minds  work. 
Given  this  basis  of  logic,  the  process  of  coming  to  possess  our 
meanings— and  in  that  sense,  our  world— in  common,  is  secured 


1926] 


Lewis:  The  Pragmatic  Element  in  Knowledge 


215 


by  the  business  of  living  together  and  the  methods  of  naming, 
pointing,  and  learning  by  imitation,  which  exhibit  the  funda- 
mental habits  of  the  social  animal.  In  the  end,  the  practical 
criterion  of  common  meaning  is  congruous  behavior.  Speech 
is  merely  that-  part  of  behavior  which  is  most  significant  for 
securing  the  cooperation  of  others. 

But  while  I  have  been  striving  to  make  it  plausible  that 
concepts  and  common  meanings  are  something  apart  from 
immediate  sensation,  you  have  been  preparing  an  objection,  I 
am  sure.  "This  concept,"  you  will  say,  "is  a  mere  abstraction. 
Nobody  has  one  in  his  mind  without  connecting  it  with  his 
experience  of  objects;  and  the  principal  use  of  concepts  is  to 
apply  to  and  name  perceivable  things." 

I  must  grant  this  at  once.  Indeed  it  is  one  of  the  points 
I  should  like  to  make.  The  purely  logical  pattern  of  meaning 
is  always  an  abstraction.  It  is  exactly  like  the  concepts  of  pure 
mathematics  in  this  respect,  though  other  concepts  may  often 
lack  the  simplicity  and  exactness  of  the  mathematical.  Just  as 
in  the  case  of  pure  mathematics  there  is  a  complex  and  im- 
portant set  of  logical  consequences  which  arise  merely  from  the 
definitions  of  terms,  so  also  in  the  case  of  concepts  in  general, 
the  pattern  of  logical  relations  which  is  generated  simply 
through  our  modes  of  distinguishing  and  relating,  is  something 
intrinsically  capable  of  being  separated  from  all  application 
to  things  of  sense,  and  would  then  constitute  a  definite  and 
considerable  body  of  knowledge  which  could  be  learned  merely 
by  thinking,  without  any  reference  to  the  external  world  at  all. 
Indeed  we  know  at  once  that  any  sort  of  definition  has  logical 
consequences  which  can  be  so  learned.  When  we  remember  that 
any  science,  and  even  common-sense  knowledge,  can  get  under 
way  only  through  our  bringing  to  experience  those  initial  modes 
of  classification  and  relation  which  our  definitions  embody,  we 
are  brought  to  realize  that  in  physics,  or  chemistry,  or  any  other 
department  of  knowledge,  we  do  not  study  simply  the  facts 
of  our  given  experience.    We  study  in  part  such  facts  and  in 


Ulf. 


University  of  California  Publications  in  Philosophy  [Vol.6 


part  the  consequences  of  our  own  logical  meanings,  though 
usually  without  any  separation  of  these  two. 

In  our  knowledge  of  the  external  world,  concepts  represent 
what  thought  itself  brings  to  experience.  The  other  element  is 
'the  given.'  It  represents  that  part  or  aspect  which  is  not 
affected  by  thought,  the  "buzzing,  blooming  confusion,"  as 
James  called  it,  on  which  the  infant  first  opens  his  eyes. 

It  is  difficult  to  make  a  clean  separation  of  what  is  given  in 
experience  from  all  admixture  of  conceptual  thinking.  The 
given  is  something  less  than  perception,  since  perception  already 
involves  analysis  and  relation  in  recognition.  One  cannot 
express  the  given  in  language,  because  language  implies  con- 
cepts, and  because  the  given  is  just  that  element  which  cannot 
be  conveyed  from  one  mind  to  another,  as  the  qualia  of  color  can 
never  be  conveyed  to  the  man  born  blind.  But  one  can^so  to 
speak,  point  to  the  given.  There  are  some  of  us  who  enjoy 
music  passively.  We  just  soak  it  in,  as  the  infant  may  confront 
the  world  in  his  first  conscious  perception.  We  are  transported 
by  it.  and  all  thought  is  put  to  sleep.  Perhaps  others  tell  us 
that  this  is  a  very  uncultivated  attitude;  that  we  do  not  hear 
the  music  at  all  but  only  a  glorious  noise.  What  they  mean 
is  that  we  do  not  analyze  our  music  and  identify  its  pattern 
of  harmony  and  melody.  Well,  for  us  who  listen  thus  passively, 
music  is  pure  given;  while  for  those  who  intellectualize  it  by 
analysis  it  may  be  something  more.  But  that  more  is  not  given; 
the  mind  brings  it  to  the  experience.  In  every  experience  there 
!■>  such  a  given  element,  though  in  very  few  does  it  have  such 
immediate  esthetic  character  that  we  are  content  to  remain 
confronting  it  without  adding  to  it  by  thought. 

Perhaps  you  see  already  that  the  mere  immediacy  of  such 
given  experience  is  never  what  we  mean  by  knowledge.  Or 
rather.  I  ought  to  say,  it  is  not  what  most  of  us  mean  by  knowl- 
edge.  There  are  some,  as  for  instance  Bergson  and  the  mystics, 
who  reserve  the  term  'knowledge'  for  precisely  such  a  state  of 
luminous  immediacy.  In  the  end,  it  is  fruitless  to  quarrel  about 
the  use  of  terms;  we  can  only  note  this  curious  exception  to 


1926]  Lewis:  The  Pragmatic  Element  in  Knowledge  217 


ordinary  parlance,  and  pass  on.  For  the  rest  of  us,  knowledge 
of  things  does  not  mean  being  sunk  in  such  immediacy,  but  an 
attitude  in  which  what  is  given  is  interpreted  and  has  jsome 
significance  for  action. 

If  I  bite  an  apple,  what  is  given  is  an  ineffable  taste.  But 
if  this  is  the  basis  of  any  knowledge,  it  is  because  I  interpret  this 
taste  as  significant  of  what  is  not  just  now  given,  of  the  quality 
of  the  apple  or  of  another  bite.  At  this  moment,  your  immedi- 
ate apprehension  of  this  thing  which  I  hold  in  my  hand  leads 
you  to  say  that  I  have  here  a  sheet  of  paper.  But  if  this  should 
suddenly  explode,  or  if  I  should  proceed  to  swallow  it  and  smile, 
you  might  revise  that  judgment  and  realize  that  it  went  quite 
beyond  what  was  absolutely  given  in  perception.  Or  we  might 
just  now  hear  a  chirring,  chugging  noise  which  would  lead  us 
to  think  of  an  automobile  outside.  But  in  that  case,  we  are 
at  once  aware  how  very  much  we  have  added  to  the  given  by 
way  of  interpretation. 

If  time  permitted,  I  should  like  to  make  it  clear  that  a 
state  of  pure  immediacy  in  which  consciousness  would  just  coin- 
cide with  the  given,  would  always  be  purely  passive,  and  that 
thought  not  only  is  active  interpretation  but  that  such  interpre- 
tation is  always  significant  of  our  possible  action  and  of  the 
further  experience  to  whicl^  such  action  would  lead.  But  I  can 
omit  this,  because  it  is  a  thought  which  William  James  himself 
made  familiar.  At  least  it  will  be  clear  that  in  the  knowledge 
of  objects,  as  much  as  in  the  knowledge  of  propositions  or 
generalizations,  this  element  of  active  interpretation  must  always 
be  present.  We  do  not  have  any  knowledge  merely  by  being 
confronted  with  the  given.  Without  interpretation  we  should 
remain  forever  in  the  buzzing,  blooming  confusion  of  the  infant. 
This,  I  suppose,  is  the  biological  significance  of  thinking.  It  is 
an  activity  by  which  we  adjust  ourselves  to  those  aspects  of  the 
environment  which  are  not  immediately  apprehended  in  sensa- 
tion. Knowledge  is  always  something  which  can  be  verified. 
And  in  verification  we  always  proceed  to  something  which  is 
not  just  now  presented. 


218  University  of  California  Publications  in  Philosophy  [Vol.6 

It  is  upon  the  manner  and  the  nature  of  this  interpretation 
which  we  put  upon  the  given  that  I  should  like  to  concentrate 
our  attention.  Clearly  it  is  something  which  we  bring  to  the 
experience.  It  is  something  we  are  able  to  make  only  because 
we  confront  what  is  presented  by  the  senses  with  certain  ready- 
made  distinctions,  relations,  and  ways  of  classifying.  In  par- 
ticular, we  impose  upon  experience  certain  patterns  of  temporal 
relationships,  a  certain  order,  which  makes  one  item  significant 
of  others.  A  visually  presented  quale  of  the  object  is  a  sign 
of  the  way  it  would  taste  or  feel.  The  taste  of  it  now  is  a  sign 
of  the  taste  of  the  next  bite  also.  The  way  yonder  door  looks 
to  me  now  is  a  sign  of  the  distance  I  must  walk  to  reach  it  and 
the  position  in  which  I  must  put  my  hand  to  open  it.  It  is  by 
interpretation  that  the  infant's  buzzing,  blooming  confusion 
gives  way  to  an  orderly  world  of  things.  Order,  or  logical 
pattern,  is  the  essence  of  understanding.  Knowledge  arises 
when  some  conceptual  pattern  of  relationships  is  imposed  upon 
the  given  by  interpretation. 

Moreover,  as  we  have  seen,  it  is  only  this  conceptual  element 
of  order  or  logical  pattern  which  can  be  conveyed  from  one 
mind  to  another.  All  expressible  truth  about  our  world  is 
contained  in  such  relations  of  order,  that  is,  in  terms  of  concepts 
we  find  applicable  to  what  is  presented  in  sense. 

Now  the  concepts  which  we  thus  impose  upon  given  experi- 
ence are  almost  always  such  as  we  have  formulated  only  as  the 
need  for  them  arose.  Experience  itself  has  instigated  our  atti- 
tudes of  interpretation.  The  secret  of  them  lies  in  purpose  or 
interest.  It  is  because  our  concepts  have  so  generally  this 
pragmatic  origin  that  I  began  with  the  one  illustration  where 
the  case  is  clearly  different.  Though  elementary  mathematics 
is  historically  rooted  in  practical  need,  mathematical  concepts 
have  some  of  them  a  quite  different  origin.  The  mathematician 
has  a  whole  cupboardful  of  such  conceptual  systems  for  which 
nobody  has  found  as  yet  any  useful  application.  All  concepts 
have  intrinsically  the  possibility  of  such  separate  status;  and 
all  truth  or  knowledge  represents  an  order  which  is  capable 


1926]  Lewis:  The  Pragmatic  Element  in  Knowledge  219 


of  being  considered,  like  mathematical  systems,  in  abstracto. 
The  business  of  learning,  and  the  process  by  which  mind  has 
conquered  the  world  in  the  name  of  intelligibility,  is  not  a 
process  in  which  we  have  passively  absorbed  something  which 
experience  has  presented  to  us.  It  is  much  more  truly  a  process 
of  trial  and  error  in  which  we  have  attempted  to  impose 
upon  experience  one  interpretation  or  conceptual  pattern  after 
another  and,  guided  by  our  practical  success  or  failure,  have 
settled  down  to  that  mode  of  construing  it  which  accords  best 
with  our  purposes  and  interests  of  action. 

Moreover,  this  mode  of  successful  interpretation  may  not 
be  dictated  unambiguously  by  the  content  of  experience  itself. 
The  famous  illustration  of  this  fact  that  William  James 
made  use  of  is  probably  the  best.  For  a  thousand  years  men 
interpreted  the  motions  of  the  heavens  in  terms  of  Ptolemy's 
astronomy,  based  on  a  motionless  earth.  Then  gradually  this 
was  given  up  in  favor  of  the  Copernican  system  of  moving 
earth  and  fixed  stars.  Those  who  argued  this  issue  supposed 
they  were  discussing  a  question  of  empirical  fact.  We  now 
perceive  that  such  is  not  the  case.  All  motion  is  relative.  The 
question  what  moves  and  what  is  motionless  in  the  heavens  is 
one  which  cannot  be  settled  merely  by  experience.  But  one 
choice  of  axes  is  highly  convenient,  resulting  in  relatively  simple 
generalizations  for  the  celestial  motions  and  enabling  celestial 
and  sublunary  phenomena  to  be  reduced  to  the  same  equations, 
while  almost  insurmountable  complexity  and  difficulty  attend 
the  other  choice.  Theoretically  if  any  system  of  motions  is 
describable  with  respect  to  one  set  of  axes,  it  is  also  describable 
in  terms  of  any  other  set  which  moves  with  reference  to  the 
first  according  to  any  general  rule.  So  that  the  issue  between 
the  Ptolemic  and  Copernican  choice  of  a  frame  of  motion  cannot 
be  decided  on  the  ground  that  one  describes  the  facts,  the  other 
not.  Rather  the  one  describes  the  facts  simply  and  conveniently, 
the  other  complexly  and  most  inconveniently.  The  only  issue 
is,  pragmatic. 


220  University  of  California  Publications  in  Philosophy       [Vol.  6 

Similarly  with  the  recent  controversy  between  the  physics 
of  relativity  and  the  Euclidean-Newtonian  mechanics.  Perhaps 
you  and  I— certainly  I— do  not  understand  the  intricacies  of 
Einstein,  but  so  much  we  have  gathered:  That  since  all  motion 
is  relative,  and  since,  further,  whatever  happens  at  some  distant 
point  is  known  to  us  only  by  the  passage  of  an  effect  through 
space  and  time,  we  cannot  measure  space  without  some  assump- 
tion about  time,  or  time  without  assumptions  about  space  and 
the  laws  of  matter  which  govern  clocks,  and  so  on.  Therefore 
at  the  bottom  of  our  interpretation  of  events  in  the  physical 
universe  there  must  be  some  fundamental  assumptions,  or  defini- 
tions and  criteria,  to  which  empirical  evidence  cannot  simply 
say  yes  or  no.  One  set  of  assumptions — the  relativity  ones — 
means  a  reduction  in  the  number  of  independent  laws  but  a 
reorganization  of  common-sense;  the  other  set  obviates  this 
change  in  current  notions  about  space  and  time  but  condemns 
us  to  forego  the  simplification  in  fundamental  principles.  The 
determinable  empirical  issues,  such  as  the  perturbations  of  Mer- 
cury and  the  bending  of  light  rays,  are — so  we  may  venture  to 
think — by  themselves  not  decisive.  If  there  were  no  other  issue, 
we  should  find  some  way  to  accommodate  these  recalcitrant  facts 
to  the  old  categories.  The  really  final  issues  are  pragmatic 
ones  such  as  the  comprehensiveness  of  laws  and  economy  in 
unverifiable  assumption. 

From  such  striking  and  important  illustrations  to  the 
humbler  affairs  of  every  day,  is  a  far  cry.  And  time  does  not 
permit  the  introduction  of  further  examples  which  might 
bridge  the  gap.  But  does  not  history  go  to  prove  the  point? 
In  any  given  period,  there  is  some  body  of  generally  accepted 
concepts  in  terms  of  which  men  describe  and  interpret  their 
experience.  Later,  these  may  all  be  strange.  If  we  go  back 
to  the  Middle  Ages  or  to  the  civilization  of  ancient  Greece,  and 
try  to  view  the  world  as  men  then  saw  it,  only  by  an  effort  can 
we  do  so.  We  might  expect  that  the  fundamental  things — life, 
mind,  matter  and  force,  cause  and  effect — would  be  conceived  in 


1926] 


Lewis:  The  Pragmatic  Element  in  Knowledge 


221 


the  same  way.  Yet  it  is  exactly  here  that  we  find  the  greatest 
differences. 

These  facts  are  familiar  to  you,  and  I  need  not  dwell  upon 
them.  But  perhaps  I  may  pause  for  a  single  illustration. 
Among  the  ancients,  the  distinction  between  the  living  and  the 
inanimate  was  generally  drawn  between  those  things  which  were 
supposed  to  have  a  soul  which  was  the  cause  of  their  behavior 
and  development,  and  those  which  had  no  such  -  internal  prin- 
ciple which  explained  their  movements.  'Soul'  was  thus  a 
synonym  for  'the  vital,'  and  was  a  principle  of  nature,  coordi- 
nate with  the  mechanical.  Why  was  this  principle  of  distinction 
later  given  up?  Has  it  been  disproved  that  all  living  things 
have  souls?  Or  that  we  must  grant,  in  addition  to  the  mechan- 
ical causes  of  th«  phenomena  of  life,  an  internal  vital  principle 
which  explains  development?  We  can  hardly  claim  so  much. 
Really  to  explain  this  change  of  categories,  we  must  probably 
reckon,  on  the  one  side,  with  Christianity  and  similar  influences 
which,  when  they  came,  contrasted  'soul,'  as  the  spiritual  prin- 
ciple in  man,  with  the  material  body.  Thus  the  soul,  instead 
of  being  conceived  as  a  natural  cause  of  vital  phenomena,  is 
now  withdrawn  from  all  physical  significance.  On  the  other 
side,  the  advantage  of  control  which  goes  with  understanding 
the  facts  of  life,  so  far  as  possible,  in  terms  of  physics  and 
chemistry,  has  operated  to  extrude  the  idea  of  a  soul,  as  a 
natural  inner  principle,  from  any  place  in  biological  conceptions. 

With  other  fundamental  concepts,  it  is  much  the  same. 
Words  such  as  'life,'  'matter,'  'cause,'  and  so  on,  have  been 
used  since  thought  began,  but  the  meanings  of  them  have  con- 
tinuously altered.  There  is  hardly  a  category  or  principle  of 
explanation  which  survives  from  Aristotle  or  the  science  of  the 
Middle  Ages.  Quite  literally,  men  of  those  days  lived  in  a 
different  world  because  their  instruments  of  intellectual  inter- 
pretation were  so  different.  To  be  sure,  the  telescope  and 
microscope  and  the  scientific  laboratory  have  played  an  im- 
portant part.  As  time  goes  on,  the  body  of  familiar  experience 
widens.    But  that  hardly  accounts  for  all  the  changed  interpre- 


-  -  - 


University  of  California  Publications  in  Philosophy  [Vol.6 


tat  ion  which  history  reveals.  No1  sense  observation  alone,  but 
accord  with  human  bent  and  need,  must  be  considered.  The 
motive  to  control  external  nature  and  direct  our  own  destiny, 
was  always  there.  Old  principles  have  been  abandoned  not 
only  when  they  disagreed  with  newly-discovered  fact,  but  when 
they  proved  unnecessarily  complex  and  bungling,  or  when  they 
failed  to  emphasize  distinctions  which  men  felt  to  be  important. 

When  things  so  fundamental  as  the  categories  of  space  and 
time,  the  laws  of  celestial  mechanics,  and  the  principles  of 
physics,  are  discovered  to  depend  in  part  upon  pragmatic  choice; 
when  history  reveals  continuous  alteration  in  our  basic  concepts, 
and  an  alteration  which  keeps  step  with  changing  interests;  and 
when  we  recognize  that  without  interpretation  it  is  not  a  world 
at  all  thai  is  presented  to  us,  but  only,  so  to  speak,  the  raw 
material  of  a  world;  then  may  it  not  plausibly  be  urged  that, 
throughout  the  realm  of  fact,  what  is  flatly  given  in  experience 
does  not  completely  determine  truth — does  not  unambiguously 
fix  the  conceptual  interpretation  which  shall  portray  it? 

In  short,  if  human  knowledge  at  its  best,  in  the  applications 
of  mathematics  and  in  the  well  developed  sciences,  is  typical 
of  knowledge  in  general,  then  the  picture  wTe  must  frame  of  it  is 
this:  that  there  is  in  it  an  element  of  conceptual  interpretation, 
theoretically  always  separable  from  any  application  to  experi- 
ence and  capable  of  being  studied  in  abstraction.  When  so 
isolated,  concepts  are  like  the  Platonic  ideas,  purely  logical 
entities,  constituted  by  the  pattern  of  their  systematic  relations. 
There  is  another  element,  the  sensuous  or  given,  likewise  always 
separable  by  abstraction,  though  we  should  find  it  pure  only 
in  a  mind  which  did  not  think  but  only  felt.  This  given  element, 
or  stream  of  sensation,  is  what  sets  the  problem  of  interpretation, 
when  we  approach  it  with  our  interests  of  action.  The  function 
of  thought  is  to  mediate  between  such  interests  and  the  given. 
Knowledge  arises  when  we  can  frame  the  data  of  sense  in  a  set 
of  concepts  which  serve  as  guides  for  action,  just  as  knowledge 
of  space  arises  when  we  can  fit  a  geometrical  interpretation  upon 
our  direct  perception  of  the  spatial.    The  given  experience  does 


1926] 


Lewis:  The  Pragmatic  Element  in  Knowledge 


223 


not  produce  the  concepts  in  our  minds.  If  it  did,  knowledge 
would  be  pure  feeling,  and  thought  would  be  superfluous.'  Nor 
do  the  concepts  evoke  the  experience  which  fits  them,  or  limit 
it  to  their  pattern.  Rather  the  growth  of  knowledge  is  a  process 
of  trial  and  error,  in  which  we  frame  the  content  of  the  given 
now  in  one  set  of  concepts,  now  in  another,  and  are  governed  in 
our  final  decision  by  our  relative  success — by  the  degree  to  which  i 
our  most  vital  needs  and  interests  are  satisfied. 

If  this  is  a  true  picture,  then  there  are  three  elements  in 
knowledge,  or  three  phases  of  the  relation  of  mind  to  the  objects 
of  thought.  First,  there  is  the  kind  of  knowledge  which  we  have 
in  abstract  mathematics,  and  the  kind  of  truth  which  concerns 
purely  logical  implications.  There  is  this  type  of  truth  for  all 
concepts  so  far  as  they  are  precise  and  clear.  Our  knowledge 
of  such  truth  possesses  certainty  and  finality  because  it  requires 
only  clarity  of  thought  and  is  entirely  independent  of  experience. 

This  kind  of  truth  can  be,  and  has  been,  described  in  two 
ways,  either  of  which  is  accurate  when  we  grasp  what  they  mean. 
First  is  the  way  of  Plato,  who  emphasizes  the  fact  that  abstract 
concepts  ("ideas"  he  calls  them)  are  not  created  by  the  mind. 
What  he  means  is  that  the  mathematician,  for  example,  does 
not  create  but  discovers  the  truths  that  he  portrays.  Before  the 
non-Euclidean  geometries  or  the  possibility  of  curves  without 
tangents  was  even  thought  of,  the  truth  about  them  was  forever 
fixed. 

The  second  way  of  describing  this  realm  of  abstract  entities 
is  to  note  that  such  pure  concepts  have  no  residence  outside  the 
mind.  Plato's  heaven — -so  we  should  say  from  this  second  point 
of  view — is  merely  a  fiction  to  emphasize  the  absoluteness  of 
conceptual  truth.  Without  our  thought  concepts  would  remain 
forever  in  the  dark  limbo  of  nothingness.  Moreover,  it  is  their 
usefulness,  their  applicability  to  given  experience,  which  moves 
us  to  evoke  them.  We  select,  or  call  down  from  Plato's  heaven, 
those  concepts  which  meet  our  needs.  Plato  said  we  are  "re- 
minded ' '  of  them  by  experience ;  we  are  more  likely  to  say  that 
we  invent  or  formulate  them  ourselves.    In  either  case,  two 


224  University  of  California  Publications  in  Philosophy  [Vol.6 

points  are  to  be  remarked;. first,  that  the  logical  relations  of — 
and  faience  the  truth  about — any  determinate  concept  is  fixed  and 
eternal  and  independent  of  experience.  Second,  that  what 
concepts  avc  shall  use  or  apply,  we  are  left  to  determine  ourselves 
in  the  light  of  our  needs  and  interests. 

The  second  phase  of  the  mind's  relation  to  its  objects,  is 
the  element  of  the  purely  given  in  experience.  Of  this  by  itself, 
there  is  no  truth  or  knowledge  in  the  ordinary  sense.  Yet  the 
given  has  significance.  There  is  something  which  speaks  directly 
to  us  in  just  this  presentation  of  the  senses,  in  that  immediacy 
of  color  or  of  sound  which  one  who  lacked  the  appropriate  sense- 
organ  could  never  imagine  nor  our  description  conjure  up  for 
him.  In  particular,  the  immediate  has  esthetic  significance; 
perhaps  it  may  also  have  ethical  value  and  religious  meaning. 
But  it  is  not  knowledge  in  the  usual  meaning  of  that  term, 
because  it  is  ineffable;  because  there  is  nothing  in  such  direct 
apprehension  which  calls  for  verification ;  because  by  itself  it  has 
no  reference  to  action. 

The  third  element  or  phase — the  element  which  distinguishes 
our  knowledge  of  the  external  world — is  the  active  interpretation 
which  unites  the  concept  and  the  given.  It  is  such  interpretation 
alone  which  needs  to  be  verified,  or  can  be  verified,  and  the 
function  of  it  is  essentially  practical.  Truth  here  is  not  fixed, 
because  interpretation  is  not  fixed,  but  is  left  for  trial  and  error 
to  determine.  The  criteria  of  its  success  are  accommodation  to 
our  bent  and  service  of  our  interests.  More  adequate  or  simpler 
interpretation  will  mean  practically  truer.  Old  truth  will  pass 
away  when  old  concepts  are  abandoned.  New  truth  arises  when 
new  interpretations  are  adopted.  Attempted  modes  of  under- 
standing may,  of  course,  completely  fail  and  prove  flatly  false. 
But  where  there  is  more  than  one  interpretation  which  can 
frame  the  given,  'truer'  will  mean  only  'better.'  And  after  all, 
even  flat  falsity  can  only  mean  a  practical  breakdown  which  has 
j)  roved  complete. 

At  just  this  point,  however,  we  may  easily  fall  into  misappre- 
hension.   In  speaking  thus  of  'new  truth'  and  'old  truth' 


1926]  Lewis:  The  Pragmatic  Element  in  Knowledge  225 

and  of  pragmatically  'truer'  arid  'falser,'  I  am  following  a 
usage  which  the  literature  of  pragmatism  has  made  familiar. 
But  I  think  this  is  a  little  to  be  regretted.  Most  of  the  paradoxes 
and  many  of  the  difficulties  of  the  pragmatic  point '  of  view 
cluster  about  this  notion  that  the  truth  can  change.  When  we 
see  precisely  what  it  is  that  happens  when  old  modes  of  inter- 
pretation are  discarded  in  favor  of  new  and  more  successful 
ones,  all  these  paradoxes  will,  I  think,  be  found  to  disappear. 
What  is  it  that  is  new  in  such  a  case?  The  given,  brute-fact 
experience  which  sets  the  problem  of  interpretation  is  not  new. 
And  the  concepts  in  terms  of  which  the  interpretation,  whether 
old  or  new,  is  phrased  are — remembering  Plato — such  that  the 
truth  about  them  is  eternal.  Obviously  what  is  new  is  the 
application  of  the  concept,  or  system  of  concepts,  to  experience 
of  just  this  sort.  The  concepts  are  newly  chosen  for  interpreta- 
tion of  the  given  data.  That  the  concepts  may  also  be  new  in 
the  sense  that  no  one  ever  thought  of  them  before,  does  not,  at 
bottom,  affect  the  problem  at  all. 

Historically  the  situation  is  likely  to  be  slightly  more  com- 
plex; the  body  of  data  to  be  interpreted  itself  undergoes  some 
alteration.  It  is  possible  that  old  systems  of  thought  should 
be  rejected  and  replaced  by  new,  simply  through  reflection  and 
realization  of  the  superior  convenience  of  the  novel  mode.  In 
fact,  this  has  sometimes  happened.  But  in  the  more  typical  case, 
such  change  does  not  take  place  without  the  added  spur  of  newly 
discovered  phenomena  which  complicate  the  problem  of  interpre- 
tation. The  several  factors  which  must  be  considered  are,  then : 
(1)  the  two  sets  of  concepts,  old  and  new,  (2)  the  expanding 
bounds  of  experience  in  which  what  is  novel  has  come  to  light, 
(3)  the  conditions  of  application  of  the  concepts  to  this  new 
body  of  total  relevant  experience. 

In  the  case  of  the  Copernican  revolution,  it  was  the  invention 
of  the  telescope  and  the  increasing  accuracy  of  observation 
which  mainly  provided  the  impetus  to  reinterpretation.  But 
these  new  data,  though  practically  decisive,  were  decisive  of 
simplicity  and  comprehensiveness  only.    As  we  have  seen,  celes- 


226  rninrsili/  of  California  Publications  in  Philosophy  [Vol.6 

tial  mot  ions  are  theoretically  as  capable  of  interpretation  with 
respect  to  axes  through  the  earth  as  by  reference  to  the  fixed 
stars.  Now  suppose  thai  mathematicians  and  astronomers  had 
so  much  spare  lime  thai  both  these  systems  had  been  worked  out, 
f,,r  all  the  data,  with  some  completeness.  Which  would  be  the 
l  rut h  aboul  the  heavens?  Obviously,  both.  The  laws  of  celestial 
motion  in  the  two  cases  would  be  quite  different,  and  the 
divergence  would  extend  beyond  astronomy  to  physics.  But 
both  would  be  absolutely  and  eternally  true  in  their  own  terms. 
The  one  would  he  better  truth,  the  other  worse,  from  the  point 
of  view  of  workability.  But  except  in  the  practical  sense  that 
we  must  stick  to  the  one  or  the  other  all  through  and  cannot 
apply  them  piecemeal,  they  could  not  contradict  one  another. 

Tins  situation  is  not  altered  by  any  thought  that  newly  dis- 
covered fact  may  play  another  than  the  pragmatic  role,  and  be 
decisive  of  truth  in  a  deeper  sense.  In  any  case,  if  old  prin- 
ciples were  ever  true,  they  must  remain  true — in  .  terms  of  the 
old  concepts.  To  the  extent  that  new  evidence  can  render  the 
old  concepts  absolutely  inapplicable,  the  "old  truth"  never  was 
anything  but  an  hypothesis,  and  is  now  proved  flatly  false. 
It  is  not,  I  hope,  the  point  of  the  pragmatic  theory  of  knowledge 
to  reduce  all  truth  thus  to  hypothesis.  That  would  be  nothing 
but  a  cheerful  form  of  skepticism. 

Bather  the  point  is — at  least  the  point  which  I  should  like 
to  make — that  the  truths  of  experience  must  always  be  relative 
to  our  chosen  conceptual  systems  in  terms  of  which  they  are 
expressed ;  and  that  amongst  such  conceptual  systems  there  may 
be  choice  in  application.  Such  choice  will  be  determined,  con- 
sciously or  unconsciously,  on  pragmatic  grounds.  New  facts 
may  cause  a  shifting  of  such  grounds.  When  this  happens, 
nothing  literally  becomes  false,  and  nothing  becomes  true  which 
was  not  always  true.  An  old  intellectual  instrument  has  been 
given  up.    Old  concepts  lapse  and  new  ones  take  their  place. 

It  would  be  a  hardy  soul  who  should  read  the  history  of 
science  and  of  common-sense  ideas  and  deny  that  just  this  shift 
of  concepts  on  pragmatic  grounds  has  frequently  had  important 


1926]  Lewis:  The  Pragmatic  Element  in  Knowledge  227 

place  in  the  advance  of  thought.  That  historically  men  sup- 
pose they  are  confronted  simply  with  a  question  of  absolute 
truth  when  they  debate  Copernican  versus  Ptolemaic  astronomy, 
mechanism  versus  vitalism,  relativity  versus  Newtonian  mechan- 
ics, and  so  on,  does  not  remove  the  possibility  that  the  really 
decisive  issues  may  often  be  pragmatic. 

Pragmatists  have  sometimes  neglected  to  draw  the  distinction 
between  the  concept  and  immediacy,  between  interpretation  and 
the  given,  with  the  result  that  they  may  seem  to  put  all  truth 
at  once  at  the  mercy  of  brute-fact  experience  and  within  the 
power  of  human  choice  or  in  a  relation  of  dependence  upon 
human  need.  But  this  would  be  an  attempt  to  have  it  both 
ways.  The  sense  in  which  facts  are  brute  and  given  cannot  be 
the  sense  in  which  the  truth  about  them  is  alterable  to  human 
decision.  The  separation  of  the  factors  is  essential.  On  the 
one  side,  we  have  the  abstract  concepts  themselves,  with  their' 
logical  implications.  The  truth  about  these  is  absolute,  and 
knowledge  of  them  is  a  priori.  On  the  other  side,  there  is  thej 
absolute  datum  of  the  given.  But  it  is  between  these  two,  in 
the  determination  of  those  concepts  which  the  mind  brings  to 
experience  as  the  instruments  of  its  interpretation,  that  a  large 
part  of  the  problem  of  fixing  the  truths  of  science  and  our 
common-sense  knowledge  has  its  place.  Wherever  such  criteria 
as  comprehensiveness  and  simplicity,  or  serviceability  for  the 
control  of  nature,  or  conformity  to  human  bent  and  human 
ways  of  acting,  play  their  part  in  the  determination  of  such  con- 
ceptual instruments,  there  is  a  pragmatic  element  in  knowledge. 


191682 


\ 


UNIVERSITY  OP  CALIFORNIA  PUBLICATIONS—  (Continued) 
Vol.  IV 

lies  and  Tendencies  in  Contemporary  Philosophy.  Lectures 
delivered  before  the  Philosophical  Union,  University  of  Cali- 
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jfejoy.  The  Anomaly  of  Knowledge. 

ims.  The  Nature  and  Habitat  of  Mind. 

II.  The  Present  Status  of  the  Theory  of  Value. 

•per.  The  Equivocation  of  Value. 

iizen.  The  Philosophical  Aspects  of  the  Theory  of  Relativity, 
jjwenberg.  The  Metaphysics  of  Critical  Realism, 
np  Smith.  Whitehead's  Philosophy  of  Nature. 

PI  .  ;    Vol.  V 

ays  in  Metaphysics.  Lectures  delivered  before  the  Philosophical 
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rd.   The  Character  of  Metaphysical  Inquiry. 

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lines.   The  Method  of  Metaphysics. 

twenberg.  The  Idea  of  the  Ultimate. 

ill.  Metaphysics  and  Value. 

stms.  Reason  and  Experience. 

re  joy.  The  Discontinuities  of  Evolution. 

|  Vol.  VI 

mes.  The  Method  and  Presuppositions  of  Group  Psychology  . . .  2.00 

jry.   A  Modernist  View  of  National  Ideals ....     .25 

wis.  The  Pragmatic  Element  in  Knowledge     .35 

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uns.  Norms  and  Reason. 

tzen.  Regulative  Principles  in  Physical  Science. 

,11.  Naturalism  and  Norms. 

>per.  Standard  Value. 

•ker.  The  Harmony  Principle  in  Ethics. 

wenberg.  Is  Metaphysics  Descriptive  or  Normative? 

tltague.  Time  and  the  Fourth  Dimension. 


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